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Intel i9 7940X ¦ Overclocking the Beast ¦ HELP

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New Member
Nov 22, 2018
Right, firstly - I'm new here ( this is what overclocking has driven me to ). So hello to everyone, and especially those that have taken the time to review my thread .

I haven't been on any overclocking forums for many many years; but I've just built a beautiful new rig and have been growing a couple gray hairs trying to maximise my return on investment. Just to clarify, I'm not your standard 'hey I got a new machine and want to overclock it, what do I do?' kind of guy, I grasp technology and the associated technical knowledge that comes with it. I'm not an experienced overclocker by any stretch, but I've overclocked many systems successfully and they've lasted a long time - until now, when I re-built the 'The Rig'. :clap:

About 'The Rig' then:

CPU: Intel i9 7940X - 14-Cores, 28-Threads
Motherboard: Aorus Gaming Ultra
Memory: HyperX Predator 32GB 2996Mhz (4x 8GB Modules)
SSD: 3x 1TB NVMe Smasung 970 EVO
GPU: 970 GTX G1 WindForce ( I don't game, don't judge me! I am a photographer/videographer :) CPU is king for me )
Cooling: AIO Water Cooling Loop Thermaltake Flow ring RGB. 2 large front case intake fans, 3 120MM exhaust fans to remove case air.
BIOS: F2 - I tried the latest BIOS, which support micro code updates and also the new 99XX series i9's - but the F2 BIOS just feels more stable to me.
PSU: CoolerMaster Gold Rated V850 850Watt Power Supply.

Now the embaressing part:

I've tried to overclock, even got 4.8GHz @ 105C runnig Cinebench / Prime95 torture test for 15 minutes. But randomly, my system would freeze ( my mouse would also stutter on occassions ). So I declocked, to 4.5 Ghz, randomly my system would again freeze or BSOD.

I did this with XMP, without XMP, same result. Infact XMP results in lock ups, though MemTest for 4 hours no isuses so.... it's defintely a setting on the motherboard somewhere.

Remember where I said I was by no means an OC god? Yes well, that means I don't really understand VCore voltages, offsets - I did enable AVX @ -3 and AVX512 at 5 - as I use Adobe applications that BSOD without these two settings - so they're configured and everything else is stock.

Anyway, I've told you what I've spent most of my days doing ( pulling my F***** hair out ).

I'm extremely hopefuly there is someone here who can possibly tell me what the issue is? Is there further i9 micro-code updates? Is this why it freezes? Right now I'm stock and all is good (except for AVX & AVX512 values).

My RAM is running at default 2400Mhz... quotes it can run 2996 easily. So I wonder what I can do to get it run at those speeds in conjunction with what I need to adjust in BIOS to achieve stable overclocks on the 7940X.

4.3GHz turbo boost is PLENTY, but I'd love 4.6GHZ... or even 4.5Ghz. ( Okay man, I'll even settle for 4.4GHz.... as long as I get more than what I paid for :mad: LOL ). I just want somethin back from a system that is capable of running more.

Is there anyone here who is willing to talk to me and help me get above stock. I just want a 'little extra', but with stability - nothing worse then the system locking up when I am just taking it for a very light spin browsing the net, for example.

Thanks in advance guys.
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I wouldn't run this CPU at more than 1.2V on AIO cooling. This is about max you can set so CPU won't overheat. In the same time it should be enough to set 4.5-4.7GHz, depends on the CPU itself.
I would try to set everything at auto but change CPU ratio to x45-47 and CPU voltage to 1.2V and check how it works. Additional voltages and other settings should be optimal at auto.

When you stabilize the CPU then we can start playing with memory but start from something.
Thanks for your reply Woomack. And thanks also for the welcome.

Happy to set the ratio to 45 for instance, on the aorus Gaming Ultra, 'VCore' doesn't exist as such, I'm sure it's disguised as something else. Something like CPU PWR Offset and has increments of 0.500 - I'm not familiar with reading this - do you have any idea where the VCore adjustment can be made on Aorus motherboards?
I was using only ASUS, ASRock and Supermicro X299 motherboards so I'm not sure how it looks like on Gigabyte. I guess you can post some BIOS screenshots. Most new motherboards have it under F12 or other key.
I guess there are also Gigabyte users on the forums who could give you some tips.
To clarify, if the VCore is set to low, that could cause freezing, bsod?
Right, I spent a couple of hours last night following a guide from gigabyte for the 7900X series.

VCore at 1.3V............. and a 200mhz OC still caused my system to crash an bsod/freeze. Surely above 1.3VCore is not ideal? Infact I have to downclock it to 4.2Ghz and disable turbo boost tech to get it stable.
My 7900X requires 1.15V at 4.5GHz and 1.20V at 4.7GHz. Using water cooling under full load it passes 90°C at ~1.22V. 1.25V would cause throttling.

Too low voltage will for sure cause PC freezing, bsod or various errors during calculations. Too high voltage will cause the same because of overheating.

To check how high you can set voltage and be sure it's maximum possible voltage on your rig, simply set manually something like 4GHz and check at how high voltage it will reach 95°C (give it maybe 20-30 mins to stabilize at this temp). It's because CPU frequency is not really affecting max temp. So once you find max voltage then lower it slightly by let's say 0.01V and start raising CPU ratio. One multi up and stability test for let's say 1h.

For CPU only use Prime95 small FFT or AIDA64 FPU (only FPU). AIDA64 is usually showing a bit lower max temp because of different test pattern but will show stability in similar way.

During the CPU tests keep memory clock at 2133-2400 or simply auto. Don't use XMP as it may raise additional voltages and it may change at each higher CPU clock.

Monitor voltage under load and idle. Try to keep it under load as high as it is set in BIOS. Use something like hwinfo64 or hardwaremonitor or simply Gigabyte software if you are sure it shows correct values and info about each core separately.
If voltage is going too high or too low under CPU load then adjust it with LLC options in BIOS. I have no idea how it works on Gigabyte boards so you have to check it yourself or read some guides.
I've had to de-clock it to 3.8GHz. Seems stable now. For some reason, with the latest drivers / bios- LightRoom and Photoshop/Premiere Pro BSOD. AVX offsets of 3 and 5(for512) seem to help.
I don't think it's the CPU problem. More like something is wrong in BIOS or voltage is too high and it's causing overheating during more demanding operations.
Could be 'Optmised Defaults' setting in BIOS that isn't actually applying the defaults perhaps?
I realize this is an old thread, but no matter how much voltage I give (went to 1.3v), I can't get my 7940x above 4.0 ghz. Clicks off after it boots and I try a benchmark. gigabyte x299 gaming 9 mb.